Dirt-bike racing has cost Tyler Bowers two broken legs, more than 10 broken fingers (he's broken each finger in both hands at least once), a collapsed lung, a lacerated spleen and so many concussions that he's lost track.

Is this a great life or what?

"I just love being on a bike; it's as exciting as it gets," says Bowers, the reigning champion of Arenacross, an engine-roaring, dirt-pounding indoor competition coming to Baltimore's 1st Mariner Arena this weekend. "Every race is the most intense eight minutes, nine minutes of your life."

It's certainly among the biggest adrenaline rushes you'll ever have — or see: Racing often-airborne bikes for lap after lap on an arena floor transformed, thanks to some 150 truckloads of soil, into a roller coaster made entirely of dirt. Racers roar, fly, bump, splat and otherwise do battle with one another — no holds barred.

"It's the most intense action you'll ever see," promises Bowers, who's been racing professionally for three years — and first got on a dirt bike, he swears, when he was only 18 months old.

"My dad rode, and he never wanted to leave me behind — he always wanted to make sure I was part of his life," says Bowers, whose dad, Tim, never rode professionally but loved dirt-biking nonetheless. "Whenever he went out, he made sure to take me with him."

Not that Bowers claims to remember that first ride — even without any concussions, most people would have trouble remembering what they did at a year-and-a-half. But for Bowers, now 20, memories of those early riding days come back frequently.

"When I'm riding a four-wheeler in the desert, sometimes that dust smell, it takes me back," he says. "I was 4 when we moved from California, but that sense of smell — that dust and dirt out in the middle of the desert, it throws me back to that memory."

As a dirt-bike rider for the better part of two decades, Bowers has gotten to know well the smell of flying dirt. Like its older cousins motocross (which is done outdoors in the open air) and supercross (done in stadiums and outdoor arenas), arenacross takes its riders across determinedly rough terrain, filled with hills and gullies and the sort of obstacles sane bikers generally seek to avoid.

It's fast — riders achieve speeds up to 40 mph indoors. It's loud — all those gunning motorcycles make noise that reverberates within the venue's walls. And it's raucous, employing fireworks and light shows to rev up the crowd.

"The tracks are very tight and very technical, which correlates into tighter, closer racing where sometimes riders are flying 60 feet in the air with just a few feet in between them," says Mike Muye, director of operations for AMA Arenacross. "The intimate setting of an arena also allows fans to really see and get a feeling for what these athletes are facing."

The rules are simple: Riders participate in heats, and the top finishers make it to the finals. There's an additional heat, a last-chance qualifier, for those who didn't make it the first time. The competition climaxes with a 25-lap, anything-goes race for the event championship.

There's also a Dash-for-the-Cash, a three-lap, winner-take-all race in which only the top three qualifiers compete. The amount of cash varies, depending on the generosity of the crowd.

"Everybody stays pretty close to one another in the race, and it's as intense as possible," says Bowers, noting that the purse can be upward of $800. "It's actually my favorite event."

The intensity of the dash may appeal especially to Bowers, but when it comes to dirt-bike racing, "favorite" is clearly a relative term for the Californian who splits his time between his farm in Kentucky and his winter home in Corona, Calif., about 40 miles from Los Angeles.

"I love Kentucky, but it's really cold in the winter," he says. "It's really hard to get anything done there, as far as training, in the winter. A lot of the industry's out here, too."

Training is a serious factor in his success, Bowers says, something he doesn't take lightly. To hear Bowers tell it, his life is split into three parts: training, competing and maybe the occasional couple of hours' sleep.

"I wake up, I eat breakfast, then I go ride all day," Bowers says. "I eat lunch while I'm out, then I ride a little bit more. When I get done with that, I go home, work with the bikes, wash the bikes, then go to the gym to get better on the bike.

"It's all day long," he says without a trace of weariness. "It's my life."

OK, maybe not his entire life. He admits to fishing occasionally while home on the farm, and being from Kentucky, he owns some horses. Not that he rides them. Too dangerous.

"I try to stay off them," he says, sounding an uncharacteristic note of caution. "They cause too many injuries."

The second meet of this season's AMA Arenacross series runs through Sunday at 1st Mariner Arena, 201 W. Baltimore St. Action is set to begin at 7:30 p.m. today and Saturday, with amateur racing set for 10 a.m. Sunday. Tickets, available through Ticketmaster at 1-800-547-7328 or ticketmaster.com, are $10-$40 today and Saturday, $10-$20 Sunday. Venue information: 410-347-2020 or 1stmarinerarena.com.